Style: Fix vertical margins of def lists w/o <p>s to match those with (…

…#2427)

* Style: Fix vertical margins of def lists w/o <p>s to match those with

* Style: Specify line-height without rem

pep_sphinx_extensions/pep_theme/static/style.css

@@ -21,7 +21,7 @@ html {
     overflow-y: scroll;
     -webkit-font-smoothing: antialiased;
     margin: 0;
-    line-height: 1.4rem;
+    line-height: 1.4;
     font-weight: normal;
     font-size: 1rem;
     font-family: "Source Sans Pro", Arial, sans-serif;
@@ -41,7 +41,7 @@ p {margin: .5rem 0}
 
 /* Header rules */
 h1 {
-    line-height: 2.3rem;
+    line-height: 2.3;
     font-size: 2rem;
     font-weight: bold;
     margin-top: 2rem;
@@ -127,6 +127,9 @@ details > summary {
 dl dt {
     font-weight: bold;
 }
+dl dd {
+    margin-bottom: 0.5rem;
+}
 
 /* Horizontal rule rule */
 hr {
@@ -195,7 +198,7 @@ section#pep-page-section > header {
 }
 section#pep-page-section > header > h1 {
     font-size: 1.1rem;
-    line-height: 1.4rem;
+    line-height: 1.4;
     margin: 0;
     display: inline-block;
     padding-right: .6rem;